Does anyone know where I could pick up a set of standard, OEM rings for my RT2? I haven't found much of anything on good ol' eBay. When I bought the bike  it seemed to run just fine, but it seems wrong to pull the jug as part of the restoration and not replace the rings while I have things apart. The cylinder and piston look pretty good with about 1800 miles on the bike, but it goes against my nature not to at least hone it and replace the rings.

My first port of call would be Enduronut or DEET on this forum. If no luck, then there is this set in Germany (see link).

Yamaha 308-11610-01-00 PISTON RING SET STD Genuine NEW NOS xn8425 | eBay

My thought is that a routine "honing and ring replacement" may do more harm than good.

First question is if the bike has good compression and little to no piston rattle. And then when inside, signs of blowby.

I always think the best thing to do is have a QUALIFIED machinist measure the piston to cylinder clearance. (someone that knows the old two strokes and follows specs is best.)

If clearance is in spec, then you can also measure ring gap to get an idea of the ring wear. Or in a pinch, just measure ring gap. If gap is in spec, or very close to within spec, I would never hone and replace the rings.

Yamaha chrome rings are tough... if a true 1800 miles, in my opinion and experience, rings have probably just seated in.

I also can't remember any Yamaha Enduro manual recommending routine ring replacement? (I could be wrong about that) If Yamaha rings are really worn enough for replacement, then it's probably time to bore to the next oversize and replace the piston and rings?

Bikenut71,

I can second the recommendations of MarkT. I have plenty of experience with these. I raced one for over a year, HARD, and I never needed to replace rings or hone the cylinder The only time I have ever honed a cylinder on one of these,.is when I had one bored (by an old 2-stroke machinist) and the guy did a final hone after boring the cylinder. My current RT-3 is now 1st over and runs like a top!

Hammer